The medical treatments heretofore known that relate to stabilization of the upper cervical spine are limited by poor occipital bone purchase and multiple attachment points for screws with subsequent construct failure at the cranio-cervical junction. Conventional systems for providing more reliable stabilization of the head to the neck joint rely on attachment from the neck to the back of the skull. However, in some cases the back of the skull (occiput) is unsuitable for attaching existing rigid plates and rods. For example, when suboccipital craniectomy has been performed there is no occipital bone available to which connections for stabilization can be made. Moreover, the known upper cervical spine stabilization systems use rather long, contoured rods that need to be contoured in the operating room. Such rods are subject to failure due to large bending forces.
There is therefore a need for a medical treatment that optimizes bone fusion/fixation at the occipito-cervical junction by creating a more rigid biomechanical construct that has a lower profile and can be used as a supplement or alternative to conventional fixation methods.
More particularly, there is a need for a method that eliminates the long, contoured rods.
Occipito-cervical fusion is indicated when the cranio-cervical junction is rendered unstable by various disease processes. Over the past decade, rigid fixation of the occiput using plate-screw or rod constructs with screw fixation has become popular. To increase the rigidity of the different available constructs, and due to the poor occipital bone purchase, multiple attachment points at the occiput are required. The variable regional bone thickness of the occiput, combined with the location of the dural sinuses, limits the placement and length of occipital screws, thus potentially affecting construct strength and rigidity. The optimal placement of screws in the occipital bone is technically demanding and in cases where suboccipital craniectomy is performed the area available for hardware placement is even more restricted.
Thus there is a need for an improved apparatus that does not require rigid fixation of the occiput using plate-screw or rod constructs with screw fixation.
There is also a need for a system that does not require multiple attachment points at the occiput.
However, in view of the prior art taken as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the identified needs could be fulfilled.